1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * The USB Monitor, inspired by Dave Harding's USBMon. 4 * 5 * This is a text format reader. 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/list.h> 10 #include <linux/usb.h> 11 #include <linux/slab.h> 12 #include <linux/sched/signal.h> 13 #include <linux/time.h> 14 #include <linux/ktime.h> 15 #include <linux/export.h> 16 #include <linux/mutex.h> 17 #include <linux/debugfs.h> 18 #include <linux/scatterlist.h> 19 #include <linux/uaccess.h> 20 21 #include "usb_mon.h" 22 23 /* 24 * No, we do not want arbitrarily long data strings. 25 * Use the binary interface if you want to capture bulk data! 26 */ 27 #define DATA_MAX 32 28 29 /* 30 * Defined by USB 2.0 clause 9.3, table 9.2. 31 */ 32 #define SETUP_MAX 8 33 34 /* 35 * This limit exists to prevent OOMs when the user process stops reading. 36 * If usbmon were available to unprivileged processes, it might be open 37 * to a local DoS. But we have to keep to root in order to prevent 38 * password sniffing from HID devices. 39 */ 40 #define EVENT_MAX (4*PAGE_SIZE / sizeof(struct mon_event_text)) 41 42 /* 43 * Potentially unlimited number; we limit it for similar allocations. 44 * The usbfs limits this to 128, but we're not quite as generous. 45 */ 46 #define ISODESC_MAX 5 47 48 #define PRINTF_DFL 250 /* with 5 ISOs segs */ 49 50 struct mon_iso_desc { 51 int status; 52 unsigned int offset; 53 unsigned int length; /* Unsigned here, signed in URB. Historic. */ 54 }; 55 56 struct mon_event_text { 57 struct list_head e_link; 58 int type; /* submit, complete, etc. */ 59 unsigned long id; /* From pointer, most of the time */ 60 unsigned int tstamp; 61 int busnum; 62 char devnum; 63 char epnum; 64 char is_in; 65 char xfertype; 66 int length; /* Depends on type: xfer length or act length */ 67 int status; 68 int interval; 69 int start_frame; 70 int error_count; 71 char setup_flag; 72 char data_flag; 73 int numdesc; /* Full number */ 74 struct mon_iso_desc isodesc[ISODESC_MAX]; 75 unsigned char setup[SETUP_MAX]; 76 unsigned char data[DATA_MAX]; 77 }; 78 79 #define SLAB_NAME_SZ 30 80 struct mon_reader_text { 81 struct kmem_cache *e_slab; 82 int nevents; 83 struct list_head e_list; 84 struct mon_reader r; /* In C, parent class can be placed anywhere */ 85 86 wait_queue_head_t wait; 87 int printf_size; 88 char *printf_buf; 89 struct mutex printf_lock; 90 91 char slab_name[SLAB_NAME_SZ]; 92 }; 93 94 static struct dentry *mon_dir; /* Usually /sys/kernel/debug/usbmon */ 95 96 static void mon_text_ctor(void *); 97 98 struct mon_text_ptr { 99 int cnt, limit; 100 char *pbuf; 101 }; 102 103 static struct mon_event_text * 104 mon_text_read_wait(struct mon_reader_text *rp, struct file *file); 105 static void mon_text_read_head_t(struct mon_reader_text *rp, 106 struct mon_text_ptr *p, const struct mon_event_text *ep); 107 static void mon_text_read_head_u(struct mon_reader_text *rp, 108 struct mon_text_ptr *p, const struct mon_event_text *ep); 109 static void mon_text_read_statset(struct mon_reader_text *rp, 110 struct mon_text_ptr *p, const struct mon_event_text *ep); 111 static void mon_text_read_intstat(struct mon_reader_text *rp, 112 struct mon_text_ptr *p, const struct mon_event_text *ep); 113 static void mon_text_read_isostat(struct mon_reader_text *rp, 114 struct mon_text_ptr *p, const struct mon_event_text *ep); 115 static void mon_text_read_isodesc(struct mon_reader_text *rp, 116 struct mon_text_ptr *p, const struct mon_event_text *ep); 117 static void mon_text_read_data(struct mon_reader_text *rp, 118 struct mon_text_ptr *p, const struct mon_event_text *ep); 119 120 /* 121 * mon_text_submit 122 * mon_text_complete 123 * 124 * May be called from an interrupt. 125 * 126 * This is called with the whole mon_bus locked, so no additional lock. 127 */ 128 129 static inline char mon_text_get_setup(struct mon_event_text *ep, 130 struct urb *urb, char ev_type, struct mon_bus *mbus) 131 { 132 133 if (ep->xfertype != USB_ENDPOINT_XFER_CONTROL || ev_type != 'S') 134 return '-'; 135 136 if (urb->setup_packet == NULL) 137 return 'Z'; /* '0' would be not as pretty. */ 138 139 memcpy(ep->setup, urb->setup_packet, SETUP_MAX); 140 return 0; 141 } 142 143 static inline char mon_text_get_data(struct mon_event_text *ep, struct urb *urb, 144 int len, char ev_type, struct mon_bus *mbus) 145 { 146 void *src; 147 148 if (len <= 0) 149 return 'L'; 150 if (len >= DATA_MAX) 151 len = DATA_MAX; 152 153 if (ep->is_in) { 154 if (ev_type != 'C') 155 return '<'; 156 } else { 157 if (ev_type != 'S') 158 return '>'; 159 } 160 161 if (urb->num_sgs == 0) { 162 src = urb->transfer_buffer; 163 if (src == NULL) 164 return 'Z'; /* '0' would be not as pretty. */ 165 } else { 166 struct scatterlist *sg = urb->sg; 167 168 if (PageHighMem(sg_page(sg))) 169 return 'D'; 170 171 /* For the text interface we copy only the first sg buffer */ 172 len = min_t(int, sg->length, len); 173 src = sg_virt(sg); 174 } 175 176 memcpy(ep->data, src, len); 177 return 0; 178 } 179 180 static inline unsigned int mon_get_timestamp(void) 181 { 182 struct timespec64 now; 183 unsigned int stamp; 184 185 ktime_get_ts64(&now); 186 stamp = now.tv_sec & 0xFFF; /* 2^32 = 4294967296. Limit to 4096s. */ 187 stamp = stamp * USEC_PER_SEC + now.tv_nsec / NSEC_PER_USEC; 188 return stamp; 189 } 190 191 static void mon_text_event(struct mon_reader_text *rp, struct urb *urb, 192 char ev_type, int status) 193 { 194 struct mon_event_text *ep; 195 unsigned int stamp; 196 struct usb_iso_packet_descriptor *fp; 197 struct mon_iso_desc *dp; 198 int i, ndesc; 199 200 stamp = mon_get_timestamp(); 201 202 if (rp->nevents >= EVENT_MAX || 203 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) { 204 rp->r.m_bus->cnt_text_lost++; 205 return; 206 } 207 208 ep->type = ev_type; 209 ep->id = (unsigned long) urb; 210 ep->busnum = urb->dev->bus->busnum; 211 ep->devnum = urb->dev->devnum; 212 ep->epnum = usb_endpoint_num(&urb->ep->desc); 213 ep->xfertype = usb_endpoint_type(&urb->ep->desc); 214 ep->is_in = usb_urb_dir_in(urb); 215 ep->tstamp = stamp; 216 ep->length = (ev_type == 'S') ? 217 urb->transfer_buffer_length : urb->actual_length; 218 /* Collecting status makes debugging sense for submits, too */ 219 ep->status = status; 220 221 if (ep->xfertype == USB_ENDPOINT_XFER_INT) { 222 ep->interval = urb->interval; 223 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) { 224 ep->interval = urb->interval; 225 ep->start_frame = urb->start_frame; 226 ep->error_count = urb->error_count; 227 } 228 ep->numdesc = urb->number_of_packets; 229 if (ep->xfertype == USB_ENDPOINT_XFER_ISOC && 230 urb->number_of_packets > 0) { 231 if ((ndesc = urb->number_of_packets) > ISODESC_MAX) 232 ndesc = ISODESC_MAX; 233 fp = urb->iso_frame_desc; 234 dp = ep->isodesc; 235 for (i = 0; i < ndesc; i++) { 236 dp->status = fp->status; 237 dp->offset = fp->offset; 238 dp->length = (ev_type == 'S') ? 239 fp->length : fp->actual_length; 240 fp++; 241 dp++; 242 } 243 /* Wasteful, but simple to understand: ISO 'C' is sparse. */ 244 if (ev_type == 'C') 245 ep->length = urb->transfer_buffer_length; 246 } 247 248 ep->setup_flag = mon_text_get_setup(ep, urb, ev_type, rp->r.m_bus); 249 ep->data_flag = mon_text_get_data(ep, urb, ep->length, ev_type, 250 rp->r.m_bus); 251 252 rp->nevents++; 253 list_add_tail(&ep->e_link, &rp->e_list); 254 wake_up(&rp->wait); 255 } 256 257 static void mon_text_submit(void *data, struct urb *urb) 258 { 259 struct mon_reader_text *rp = data; 260 mon_text_event(rp, urb, 'S', -EINPROGRESS); 261 } 262 263 static void mon_text_complete(void *data, struct urb *urb, int status) 264 { 265 struct mon_reader_text *rp = data; 266 mon_text_event(rp, urb, 'C', status); 267 } 268 269 static void mon_text_error(void *data, struct urb *urb, int error) 270 { 271 struct mon_reader_text *rp = data; 272 struct mon_event_text *ep; 273 274 if (rp->nevents >= EVENT_MAX || 275 (ep = kmem_cache_alloc(rp->e_slab, GFP_ATOMIC)) == NULL) { 276 rp->r.m_bus->cnt_text_lost++; 277 return; 278 } 279 280 ep->type = 'E'; 281 ep->id = (unsigned long) urb; 282 ep->busnum = urb->dev->bus->busnum; 283 ep->devnum = urb->dev->devnum; 284 ep->epnum = usb_endpoint_num(&urb->ep->desc); 285 ep->xfertype = usb_endpoint_type(&urb->ep->desc); 286 ep->is_in = usb_urb_dir_in(urb); 287 ep->tstamp = mon_get_timestamp(); 288 ep->length = 0; 289 ep->status = error; 290 291 ep->setup_flag = '-'; 292 ep->data_flag = 'E'; 293 294 rp->nevents++; 295 list_add_tail(&ep->e_link, &rp->e_list); 296 wake_up(&rp->wait); 297 } 298 299 /* 300 * Fetch next event from the circular buffer. 301 */ 302 static struct mon_event_text *mon_text_fetch(struct mon_reader_text *rp, 303 struct mon_bus *mbus) 304 { 305 struct list_head *p; 306 unsigned long flags; 307 308 spin_lock_irqsave(&mbus->lock, flags); 309 if (list_empty(&rp->e_list)) { 310 spin_unlock_irqrestore(&mbus->lock, flags); 311 return NULL; 312 } 313 p = rp->e_list.next; 314 list_del(p); 315 --rp->nevents; 316 spin_unlock_irqrestore(&mbus->lock, flags); 317 return list_entry(p, struct mon_event_text, e_link); 318 } 319 320 /* 321 */ 322 static int mon_text_open(struct inode *inode, struct file *file) 323 { 324 struct mon_bus *mbus; 325 struct mon_reader_text *rp; 326 int rc; 327 328 mutex_lock(&mon_lock); 329 mbus = inode->i_private; 330 331 rp = kzalloc(sizeof(struct mon_reader_text), GFP_KERNEL); 332 if (rp == NULL) { 333 rc = -ENOMEM; 334 goto err_alloc; 335 } 336 INIT_LIST_HEAD(&rp->e_list); 337 init_waitqueue_head(&rp->wait); 338 mutex_init(&rp->printf_lock); 339 340 rp->printf_size = PRINTF_DFL; 341 rp->printf_buf = kmalloc(rp->printf_size, GFP_KERNEL); 342 if (rp->printf_buf == NULL) { 343 rc = -ENOMEM; 344 goto err_alloc_pr; 345 } 346 347 rp->r.m_bus = mbus; 348 rp->r.r_data = rp; 349 rp->r.rnf_submit = mon_text_submit; 350 rp->r.rnf_error = mon_text_error; 351 rp->r.rnf_complete = mon_text_complete; 352 353 snprintf(rp->slab_name, SLAB_NAME_SZ, "mon_text_%p", rp); 354 rp->e_slab = kmem_cache_create(rp->slab_name, 355 sizeof(struct mon_event_text), sizeof(long), 0, 356 mon_text_ctor); 357 if (rp->e_slab == NULL) { 358 rc = -ENOMEM; 359 goto err_slab; 360 } 361 362 mon_reader_add(mbus, &rp->r); 363 364 file->private_data = rp; 365 mutex_unlock(&mon_lock); 366 return 0; 367 368 // err_busy: 369 // kmem_cache_destroy(rp->e_slab); 370 err_slab: 371 kfree(rp->printf_buf); 372 err_alloc_pr: 373 kfree(rp); 374 err_alloc: 375 mutex_unlock(&mon_lock); 376 return rc; 377 } 378 379 /* 380 * For simplicity, we read one record in one system call and throw out 381 * what does not fit. This means that the following does not work: 382 * dd if=/dbg/usbmon/0t bs=10 383 * Also, we do not allow seeks and do not bother advancing the offset. 384 */ 385 static ssize_t mon_text_read_t(struct file *file, char __user *buf, 386 size_t nbytes, loff_t *ppos) 387 { 388 struct mon_reader_text *rp = file->private_data; 389 struct mon_event_text *ep; 390 struct mon_text_ptr ptr; 391 392 ep = mon_text_read_wait(rp, file); 393 if (IS_ERR(ep)) 394 return PTR_ERR(ep); 395 mutex_lock(&rp->printf_lock); 396 ptr.cnt = 0; 397 ptr.pbuf = rp->printf_buf; 398 ptr.limit = rp->printf_size; 399 400 mon_text_read_head_t(rp, &ptr, ep); 401 mon_text_read_statset(rp, &ptr, ep); 402 ptr.cnt += snprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt, 403 " %d", ep->length); 404 mon_text_read_data(rp, &ptr, ep); 405 406 if (copy_to_user(buf, rp->printf_buf, ptr.cnt)) 407 ptr.cnt = -EFAULT; 408 mutex_unlock(&rp->printf_lock); 409 kmem_cache_free(rp->e_slab, ep); 410 return ptr.cnt; 411 } 412 413 static ssize_t mon_text_read_u(struct file *file, char __user *buf, 414 size_t nbytes, loff_t *ppos) 415 { 416 struct mon_reader_text *rp = file->private_data; 417 struct mon_event_text *ep; 418 struct mon_text_ptr ptr; 419 420 ep = mon_text_read_wait(rp, file); 421 if (IS_ERR(ep)) 422 return PTR_ERR(ep); 423 mutex_lock(&rp->printf_lock); 424 ptr.cnt = 0; 425 ptr.pbuf = rp->printf_buf; 426 ptr.limit = rp->printf_size; 427 428 mon_text_read_head_u(rp, &ptr, ep); 429 if (ep->type == 'E') { 430 mon_text_read_statset(rp, &ptr, ep); 431 } else if (ep->xfertype == USB_ENDPOINT_XFER_ISOC) { 432 mon_text_read_isostat(rp, &ptr, ep); 433 mon_text_read_isodesc(rp, &ptr, ep); 434 } else if (ep->xfertype == USB_ENDPOINT_XFER_INT) { 435 mon_text_read_intstat(rp, &ptr, ep); 436 } else { 437 mon_text_read_statset(rp, &ptr, ep); 438 } 439 ptr.cnt += snprintf(ptr.pbuf + ptr.cnt, ptr.limit - ptr.cnt, 440 " %d", ep->length); 441 mon_text_read_data(rp, &ptr, ep); 442 443 if (copy_to_user(buf, rp->printf_buf, ptr.cnt)) 444 ptr.cnt = -EFAULT; 445 mutex_unlock(&rp->printf_lock); 446 kmem_cache_free(rp->e_slab, ep); 447 return ptr.cnt; 448 } 449 450 static struct mon_event_text *mon_text_read_wait(struct mon_reader_text *rp, 451 struct file *file) 452 { 453 struct mon_bus *mbus = rp->r.m_bus; 454 DECLARE_WAITQUEUE(waita, current); 455 struct mon_event_text *ep; 456 457 add_wait_queue(&rp->wait, &waita); 458 set_current_state(TASK_INTERRUPTIBLE); 459 while ((ep = mon_text_fetch(rp, mbus)) == NULL) { 460 if (file->f_flags & O_NONBLOCK) { 461 set_current_state(TASK_RUNNING); 462 remove_wait_queue(&rp->wait, &waita); 463 return ERR_PTR(-EWOULDBLOCK); 464 } 465 /* 466 * We do not count nwaiters, because ->release is supposed 467 * to be called when all openers are gone only. 468 */ 469 schedule(); 470 if (signal_pending(current)) { 471 remove_wait_queue(&rp->wait, &waita); 472 return ERR_PTR(-EINTR); 473 } 474 set_current_state(TASK_INTERRUPTIBLE); 475 } 476 set_current_state(TASK_RUNNING); 477 remove_wait_queue(&rp->wait, &waita); 478 return ep; 479 } 480 481 static void mon_text_read_head_t(struct mon_reader_text *rp, 482 struct mon_text_ptr *p, const struct mon_event_text *ep) 483 { 484 char udir, utype; 485 486 udir = (ep->is_in ? 'i' : 'o'); 487 switch (ep->xfertype) { 488 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break; 489 case USB_ENDPOINT_XFER_INT: utype = 'I'; break; 490 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break; 491 default: /* PIPE_BULK */ utype = 'B'; 492 } 493 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 494 "%lx %u %c %c%c:%03u:%02u", 495 ep->id, ep->tstamp, ep->type, 496 utype, udir, ep->devnum, ep->epnum); 497 } 498 499 static void mon_text_read_head_u(struct mon_reader_text *rp, 500 struct mon_text_ptr *p, const struct mon_event_text *ep) 501 { 502 char udir, utype; 503 504 udir = (ep->is_in ? 'i' : 'o'); 505 switch (ep->xfertype) { 506 case USB_ENDPOINT_XFER_ISOC: utype = 'Z'; break; 507 case USB_ENDPOINT_XFER_INT: utype = 'I'; break; 508 case USB_ENDPOINT_XFER_CONTROL: utype = 'C'; break; 509 default: /* PIPE_BULK */ utype = 'B'; 510 } 511 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 512 "%lx %u %c %c%c:%d:%03u:%u", 513 ep->id, ep->tstamp, ep->type, 514 utype, udir, ep->busnum, ep->devnum, ep->epnum); 515 } 516 517 static void mon_text_read_statset(struct mon_reader_text *rp, 518 struct mon_text_ptr *p, const struct mon_event_text *ep) 519 { 520 521 if (ep->setup_flag == 0) { /* Setup packet is present and captured */ 522 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 523 " s %02x %02x %04x %04x %04x", 524 ep->setup[0], 525 ep->setup[1], 526 (ep->setup[3] << 8) | ep->setup[2], 527 (ep->setup[5] << 8) | ep->setup[4], 528 (ep->setup[7] << 8) | ep->setup[6]); 529 } else if (ep->setup_flag != '-') { /* Unable to capture setup packet */ 530 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 531 " %c __ __ ____ ____ ____", ep->setup_flag); 532 } else { /* No setup for this kind of URB */ 533 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 534 " %d", ep->status); 535 } 536 } 537 538 static void mon_text_read_intstat(struct mon_reader_text *rp, 539 struct mon_text_ptr *p, const struct mon_event_text *ep) 540 { 541 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 542 " %d:%d", ep->status, ep->interval); 543 } 544 545 static void mon_text_read_isostat(struct mon_reader_text *rp, 546 struct mon_text_ptr *p, const struct mon_event_text *ep) 547 { 548 if (ep->type == 'S') { 549 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 550 " %d:%d:%d", ep->status, ep->interval, ep->start_frame); 551 } else { 552 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 553 " %d:%d:%d:%d", 554 ep->status, ep->interval, ep->start_frame, ep->error_count); 555 } 556 } 557 558 static void mon_text_read_isodesc(struct mon_reader_text *rp, 559 struct mon_text_ptr *p, const struct mon_event_text *ep) 560 { 561 int ndesc; /* Display this many */ 562 int i; 563 const struct mon_iso_desc *dp; 564 565 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 566 " %d", ep->numdesc); 567 ndesc = ep->numdesc; 568 if (ndesc > ISODESC_MAX) 569 ndesc = ISODESC_MAX; 570 if (ndesc < 0) 571 ndesc = 0; 572 dp = ep->isodesc; 573 for (i = 0; i < ndesc; i++) { 574 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 575 " %d:%u:%u", dp->status, dp->offset, dp->length); 576 dp++; 577 } 578 } 579 580 static void mon_text_read_data(struct mon_reader_text *rp, 581 struct mon_text_ptr *p, const struct mon_event_text *ep) 582 { 583 int data_len, i; 584 585 if ((data_len = ep->length) > 0) { 586 if (ep->data_flag == 0) { 587 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 588 " ="); 589 if (data_len >= DATA_MAX) 590 data_len = DATA_MAX; 591 for (i = 0; i < data_len; i++) { 592 if (i % 4 == 0) { 593 p->cnt += snprintf(p->pbuf + p->cnt, 594 p->limit - p->cnt, 595 " "); 596 } 597 p->cnt += snprintf(p->pbuf + p->cnt, 598 p->limit - p->cnt, 599 "%02x", ep->data[i]); 600 } 601 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 602 "\n"); 603 } else { 604 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, 605 " %c\n", ep->data_flag); 606 } 607 } else { 608 p->cnt += snprintf(p->pbuf + p->cnt, p->limit - p->cnt, "\n"); 609 } 610 } 611 612 static int mon_text_release(struct inode *inode, struct file *file) 613 { 614 struct mon_reader_text *rp = file->private_data; 615 struct mon_bus *mbus; 616 /* unsigned long flags; */ 617 struct list_head *p; 618 struct mon_event_text *ep; 619 620 mutex_lock(&mon_lock); 621 mbus = inode->i_private; 622 623 if (mbus->nreaders <= 0) { 624 printk(KERN_ERR TAG ": consistency error on close\n"); 625 mutex_unlock(&mon_lock); 626 return 0; 627 } 628 mon_reader_del(mbus, &rp->r); 629 630 /* 631 * In theory, e_list is protected by mbus->lock. However, 632 * after mon_reader_del has finished, the following is the case: 633 * - we are not on reader list anymore, so new events won't be added; 634 * - whole mbus may be dropped if it was orphaned. 635 * So, we better not touch mbus. 636 */ 637 /* spin_lock_irqsave(&mbus->lock, flags); */ 638 while (!list_empty(&rp->e_list)) { 639 p = rp->e_list.next; 640 ep = list_entry(p, struct mon_event_text, e_link); 641 list_del(p); 642 --rp->nevents; 643 kmem_cache_free(rp->e_slab, ep); 644 } 645 /* spin_unlock_irqrestore(&mbus->lock, flags); */ 646 647 kmem_cache_destroy(rp->e_slab); 648 kfree(rp->printf_buf); 649 kfree(rp); 650 651 mutex_unlock(&mon_lock); 652 return 0; 653 } 654 655 static const struct file_operations mon_fops_text_t = { 656 .owner = THIS_MODULE, 657 .open = mon_text_open, 658 .llseek = no_llseek, 659 .read = mon_text_read_t, 660 .release = mon_text_release, 661 }; 662 663 static const struct file_operations mon_fops_text_u = { 664 .owner = THIS_MODULE, 665 .open = mon_text_open, 666 .llseek = no_llseek, 667 .read = mon_text_read_u, 668 .release = mon_text_release, 669 }; 670 671 int mon_text_add(struct mon_bus *mbus, const struct usb_bus *ubus) 672 { 673 struct dentry *d; 674 enum { NAMESZ = 10 }; 675 char name[NAMESZ]; 676 int busnum = ubus? ubus->busnum: 0; 677 int rc; 678 679 if (mon_dir == NULL) 680 return 0; 681 682 if (ubus != NULL) { 683 rc = snprintf(name, NAMESZ, "%dt", busnum); 684 if (rc <= 0 || rc >= NAMESZ) 685 goto err_print_t; 686 d = debugfs_create_file(name, 0600, mon_dir, mbus, 687 &mon_fops_text_t); 688 if (d == NULL) 689 goto err_create_t; 690 mbus->dent_t = d; 691 } 692 693 rc = snprintf(name, NAMESZ, "%du", busnum); 694 if (rc <= 0 || rc >= NAMESZ) 695 goto err_print_u; 696 d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_text_u); 697 if (d == NULL) 698 goto err_create_u; 699 mbus->dent_u = d; 700 701 rc = snprintf(name, NAMESZ, "%ds", busnum); 702 if (rc <= 0 || rc >= NAMESZ) 703 goto err_print_s; 704 d = debugfs_create_file(name, 0600, mon_dir, mbus, &mon_fops_stat); 705 if (d == NULL) 706 goto err_create_s; 707 mbus->dent_s = d; 708 709 return 1; 710 711 err_create_s: 712 err_print_s: 713 debugfs_remove(mbus->dent_u); 714 mbus->dent_u = NULL; 715 err_create_u: 716 err_print_u: 717 if (ubus != NULL) { 718 debugfs_remove(mbus->dent_t); 719 mbus->dent_t = NULL; 720 } 721 err_create_t: 722 err_print_t: 723 return 0; 724 } 725 726 void mon_text_del(struct mon_bus *mbus) 727 { 728 debugfs_remove(mbus->dent_u); 729 if (mbus->dent_t != NULL) 730 debugfs_remove(mbus->dent_t); 731 debugfs_remove(mbus->dent_s); 732 } 733 734 /* 735 * Slab interface: constructor. 736 */ 737 static void mon_text_ctor(void *mem) 738 { 739 /* 740 * Nothing to initialize. No, really! 741 * So, we fill it with garbage to emulate a reused object. 742 */ 743 memset(mem, 0xe5, sizeof(struct mon_event_text)); 744 } 745 746 int __init mon_text_init(void) 747 { 748 struct dentry *mondir; 749 750 mondir = debugfs_create_dir("usbmon", usb_debug_root); 751 if (IS_ERR(mondir)) { 752 /* debugfs not available, but we can use usbmon without it */ 753 return 0; 754 } 755 if (mondir == NULL) { 756 printk(KERN_NOTICE TAG ": unable to create usbmon directory\n"); 757 return -ENOMEM; 758 } 759 mon_dir = mondir; 760 return 0; 761 } 762 763 void mon_text_exit(void) 764 { 765 debugfs_remove(mon_dir); 766 } 767